That's interesting; I've not seen one like that before. I thought the manufacturer was required to include some kind of caliber marking, even if it was "MULTI".
For Form 1 purposes, I believe you'd still be OK to just have to engrave the name/city/state.
Correct, but with AR-15, the lower IS the firearm so shouldn't it be marked as well?I have always been under the impression that as long as it is marked on the barrel, you are good to go. If I recall correctly, the firearm needs to be marked, not necessarily the receiver.